My initial reaction was surprise, but Saturday has been banged up and we all knew he was a short-term answer for the position. Even if he played at a Pro Bowl level (and he hasn't, as Pro Football Focus has him ranked as the 30th-best center in 2012), how many years does he have left?

If they were facing a better defensive line, such as New England, Houston or even the Jets, or if they hadn't clinched the division, I don't see this move being made. There would be too much risk and too much on the line.

However, against the Titans this makes sense.

We're going to get a chance to see if the Packers have a center for 2013 and beyond.

This is how the Packers roll, and it's what I will always admire about them and teams like them. Sure, they're focused on making the playoffs and winning a Super Bowl this year, but they're already looking ahead as well.

Tennessee is a middle-of-the-road pass defense, with a middle-of-the-pack sack total (31), and represents an opportunity for a low-risk assessment of an important position.

We'll see how Dietrich-Smith does and how big a role he might have this season at the position.

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2) Front Seven vs. Chris Johnson

It's really easy to be fooled by Johnson's stats from last week. Sure, he had 122 yards and a touchdown against the Jets, but the vast majority of those yards came off of one run.

I don't like to play the "take away run X, then Y," but I also think perspective is vital, and the perspective is that 122 minus 94 equals a really bad day.

Of course, the takeaway here is that Johnson, despite yet another season of mediocrity since he signed his huge contract a few years back, is capable of a huge run at any time.

He's not getting any help from his offensive line either, nine times out of 10.

Meanwhile, the Packers continue to have a soft, squishy middle in terms of run defense.

This seems like it might be a bad combination for the Packers.

I'll be watching this closely to see how they do against Johnson, because that might give us an indication as to how they will do in the playoffs.

Plus, how they might do against a certain purple-garbed running back in Week 17.

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3) The Run Game

The Packers might be without Alex Green this weekend, as he's battling a concussion issue and missed Friday's practice. He's listed as questionable after missing a whole week of practices.

Green's concussion could leave DuJuan Harris and Ryan Grant to do the heavy lifting on Sunday. This will give us a good chance to see how the Packers might adapt to losing Green.

If Green does play, we'll continue to see how this backfield by committee develops. Green and Harris were splitting carries, with Grant getting a few here and there. It's not a backfield that will blow you away, but it's effective and is topping 100 yards total the last few weeks.

It does add a nice dimension to the offense, as the play-action becomes more believable when the other team actually buys you can run the ball. It isn't as good as having a single bell cow, but it works.

The pass is still the backbone of this team, but the ground game can be an important cog in the machine.

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4) Greg Jennings Tryout

It hasn't been a great year for Jennings, as he was hurt for most of it and returned to find out that the Packers had been just fine without him, thank you very much.

Jordy Nelson is out, so Jennings has the chance to show the league what he is capable of with strong performances over the next two games, especially since Nelson will probably be rested until the playoffs.

Jennings isn't coming back to Green Bay. He wants a big contract, and the Packers don't need to pay him that to have a good receiver corps. He bristles at the very mention of a franchise tag as well.

Along with Jermichael Finley, nobody has more to prove than Jennings. If he wants someone in the NFL to "show him the money," then he'd better have a huge impact.

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5) Defense

Charles Woodson may not play this weekend, but the majority of the defense that can come back this season is back now.

So let's see how good this defense can play over the next two weeks, and not only against the run, which we've already talked about. Let's see how they fare at running down Jake Locker and Christian Ponder.

Theoretically, neither should prove a huge challenge (especially Ponder, who not only has regressed, but lacks much in the way of good receivers to use), but seeing consistent pressure from this group is something that will make the fans and coaching staff happy.